Psychophysical Variations 29 



to instinct and intelligence,^ According to Groos, the 

 imitative performance, by reason of its character as pre- 

 senting a certain degree of selective learning and accom- 

 modation, tends to supplant the fixed reactions of instinct, 

 and so to put a premium on variations toward the plasticity 

 required by increasing intelligence. It now transpires that 

 Professor Groos and I are able to accept each the other's 

 position, and so reach the common view that it depends 

 upon the exigencies of the particular adaptation required by 

 the animal species as to what a particular imitative reaction 

 means. If an imperfect instinct is in the way of develop- 

 ment for a marked utility, imitation, by supplementing it, 

 would undoubtedly aid its survival and evolution in the way 

 indicated above. Yet, on the other hand, if an instinct is 

 in process of decay, — or if the conditions make its decay 

 desirable, — Professor Groos' principle would then come 

 into operation. The imitative performance would repre- 

 sent a form of variation which would be in the direction 

 of the plasticity of inteUigence, and creatures would be 

 selected who performed the function imitatively, until fur- 

 ther variations toward plasticity were forthcoming. In 

 either case, and especially in both cases working in nature 

 together, we have a clear illustration of the sort of psycho- 

 physical * togetherness,' so to speak, the indissoluble cor- 

 relation, into which the organic and the mental are welded 

 in the process of evolution. 



The fact of correlated variation, moreover, is to be car- 

 ried over to the relation between organic and mental varia- 

 tions in different individuals. Many instances are known 

 which prove it ; that they are not more numerous is due, 



1 The Play of Animals, Eng. trans. Cf. the notice of that work below, 

 Appendix C. 



